Sometimes you want to operate under a name different than what you named your LLC. This is allowed as long as you file a DBA with the Secretary of State, letting everyone know about your assumed name. This can easily be done online.
However, what if that name is already taken? You've negotiated its transfer, but how do you go about actually doing it?
Assumed names in Illinois must be "distinguishable". Therefore, you can't just apply for the assumed name with the new LLC. What do you do?
Illinois does not have a formal method of actually transferring names. The answer is that the LLC currently with that assumed name must file a Form LLC-1.20 to cancel its DBA with the state. This must be done via mail or in-person. After this, then the new LLC simply applies for the name. The reapplication can conveniently be done online.
The above is my understanding of the law. I am a lawyer, but I am not your lawyer. This post does not constitute legal advice. I make no warranty as to its accuracy or applicability to you. If you need a lawyer, get a lawyer. If you want me specifically, hire me.